A low noise nth order filter, system, and method includes a plurality of nested general immittance converters (GICs) operatively connected to one another in successive GIC stages; and a capacitor operatively connected to each of the GICs, wherein a first successive GIC stage begins at a first node located in between a previous GIC stage and a corresponding capacitor operatively connected to the previous GIC stage. A second successive GIC stage begins at a second node located in between the first node and the first successive GIC stage. The filter may further comprise a resistor operatively connected to at least one successive GIC stage, wherein the resistor is preferably located in between the first node and the first successive GIC stage.
1. A low noise nth order filter comprising:
a plurality of nested general immittance converters (GICs) directly connected to one another in successive GIC stages, wherein a transfer function of said successive GIC stages comprise at least one notch;
a passive pole directly connected to an input of only a first one of said plurality of GICs: and
a capacitor directly connected to each of the GICs,
wherein a first successive GIC stage begins at a first node located in between a previous GIC stage and a corresponding capacitor directly connected to said previous GIC stage.
2. The low noise nth order filter of claim 1 , wherein a second successive GIC stage begins at a second node located in between said first node and said first successive GIC stage.
3. The low noise nth order filter of claim 1 , further comprising a resistor directly connected to at least one successive GIC stage.
4. The low noise nth order filter of claim 3 , wherein said resistor is located in between said first node and said first successive GIC stage.
5. The low noise nth order filter of claim 4 , wherein said resistor is directly connected to an input of said at least one successive GIC stage.
6. The low noise nth order filter of claim 5 , wherein said resistor is directly connected to each of an output of said previous GIC stage and said capacitor.
7. The low noise nth order filter of claim 1 , wherein successive GIC stages attenuate out-of-band signals in a current domain thereby allowing a gain of a preceding GIC stage to be increased.
8. A method of filtering noise from an electrical signal, said method comprising:
arranging a plurality of general immittance converters (GICs) in successive GIC stages, wherein a transfer function of said successive GIC stages comprise at least one notch;
directly connecting a passive pole to an input of only a first one of said plurality of GICs; and
directly connecting a capacitor to each GIC, wherein a successive GIC stage begins at a node located in between a preceding GIC stage and a corresponding operatively connected capacitor;
introducing a signal through said GICs and corresponding capacitors; and
filtering noise from said signal in each GIC stage.
9. The method of claim 8 , further comprising directly connecting a resistor to at least one successive GIC stage.
10. The method of claim 9 , wherein said resistor is located in between said node and a successive GIC stage.
11. The method of claim 10 , further comprising directly connecting said resistor to an input of said at least one successive GIC stage.
12. The method of claim 11 , further comprising directly connecting said resistor to each of an output of said previous GIC stage and said capacitor.
13. The method of claim 8 , wherein successive GIC stages attenuate out-of-band signals in a current domain thereby allowing a gain of a preceding GIC stage to be increased.
14. A system for filtering noise from an electrical signal, said system comprising:
an antenna that receives a wireless electrical signal;
a low noise amplifier (LNA) directly connected to said antenna and amplifies said wireless electrical signal;
a mixer directly connected to said LNA combines the amplified wireless electrical signal with a local oscillator (LO) signal; and
a low noise filter directly connected to said mixer, wherein said low noise filter comprises:
a plurality of general immittance converters (GICs) arranged in successive GIC stages, wherein a transfer function of said successive GIC stages comprise at least one notch;
a passive pole directly connected to an input of only a first one of said plurality of GICs;
a capacitor directly connected to each GIC, wherein a successive GIC stage beings at a node located in between a preceding GIC stage and a corresponding capacitor directly connected to said preceding GIC stage;
a baseband component directly connected to said low noise filter; and
an analog-to-digital converter that converts the filtered wireless electrical signal to a digital signal.
15. The system of claim 14 , wherein a second successive GIC stage begins at a second node located in between said first node and said first successive GIC stage.
16. The system of claim 14 , further comprising a resistor directly connected to at least one successive GIC stage.
17. The system of claim 14 , wherein said resistor is located in between said first node and said first successive GIC stage.
18. The system of claim 17 , wherein said resistor is directly connected to an input of said at least one successive GIC stage.
19. The system of claim 18 , wherein said resistor is directly connected to each of an output of said previous GIC stage and said capacitor.
20. The system of claim 14 , wherein successive GIC stages attenuate out-of-band signals in a current domain thereby allowing a gain of said preceding GIC stage to be increased.